This invention relates to an improved warp yarn feeder of the type utilizing a driven roll for controlling tension as by holding back the warp yarn being pulled into the weaving machine.
Control of the tension on warp yarns being fed into a weaving machine has long been a problem especially when weaving heavy fabrics such as tire cord, duck fabric and the like. Heretofore, it has been the general practice to adjust the speed of the motor which drives the roll over which yarn is passed on its way to the weaving machine together with adjusting the speed of the weaving machine motor and the takeup motor. Such apparatus was of limited usefulness because of the difficulty in coordinating the action of the three motors together with sensing and exerting a positive control upon the tension on the warp yarns. The problem has persisted of maintaining constant and even tension across a web or sheet of warp yarns. Another difficulty has been the threading up of the feeding apparatus to the weaving machine because of the necessary step of passing the warp yarns over guide rolls and the driven roll for passage thence to the weaving machine.
Moreover, it is also desirable to be able to mix the types and styles of the yarns making up the warp yarn of a desired fabric and such may be accomplished if it were possible to accommodate a dual supply of warp yarns.